1. Field of Endeavor
This invention pertains to the field of plant husbandry (Class 047), specifically to the irrigation of newly planted tree seedlings and other small plants.
2. Prior Art
U.S. Pat. No. 5,896,700 Device for Watering Unattended Houseplants (McGough), describes a device which dispenses a quantity of water (typically 32 or 16 ounces) to a potted houseplant over an extended period of time (typically 1 to 2 weeks or more) without owner intervention. The bottle-type device is completely passive, operates by gravity flow, uses standard tap water, and solves a number of problems not addressed by earlier houseplant watering devices. The −700 device is comprised of three major components, one of which is a disk-shaped sandwich-type wafer constructed of several layers of gasket material, laboratory filter paper, and thin plastic, having through-holes and passages so constructed as to filter impurities from the water and control the rate at which water is released from the reservoir during the desired watering period. The −700 device dispenses the reservoir water over a specified time period, releases its water at a relatively uniform rate during the watering cycle, uses standard tap water, and is simple to manufacture and install. The −700 device has been on the market for several years and has proven to be an effective method for watering a wide variety of unattended houseplants.
Another device, called a Tree Irrigator (U.S. Pat. No. 5,117,582, Cissel, Jr. et.al) utilizes a large flexible plastic bag (typically 20 gallon capacity) which encircles the trunk of a small tree, and which contains small holes in its base to dispense water over a period of time (typically 6-8 hours) to the tree.
Other prior devices have been suggested for irrigating unattended plants, and number of these have received U.S. patents.
U.S. Pat. No. 5,443,544 (Azoulay) describes a device which uses a wick and water-absorbing sponge to transfer water to the plant.
U.S. Pat. No. 4,970,823 (Chen and Parkhurst) describes another wick-type system for dispensing water from a bottle reservoir to the soil.
U.S. Pat. No. 4,578,897 (Pazar and Petrick) describes a system for dispensing water to a water dish located below the plant.
U.S. Pat. No. 4,336,666 (Caso) describes a toroidal-shaped device which requires the operator to punch holes in the “metering nozzles” to obtain the desired flowrate.
U.S. Pat. No. 4,300,309 (Mincy) uses a “porous soil penetrating member” to dispense water from semi-toroid shaped reservoir to the soil.
Similarly, U.S. Pat. No. 4,089,133 (Duncan), U.S. Pat. No. 2,387,869 (Chatten), U.S. Pat. No. 2,595,783 (Epstein), and U.S. Pat. No. 2,375,860 (Markham) attempt to solve the problem of watering plants with various wicking, porous ceramic absorption, or multiple aperture devices.
U.S. Pat. No. 5,259,142 (Sax) employs a simple filter to restrict the flow of water from a rigid bottle, but provides no means of preventing the filter from becoming clogged by impurities in the water, nor means of sealing its filter disk against peripheral leakage.
All of the above patents describe various methods for automatically dispensing water to growing plants. However, only the first patent cited (U.S. Pat. No. 5,896,700) bears any similarity in design or operating principle to the device disclosed herein. The −700 device uses a multilayered disk made of layers of thin plastic, filter paper, and gasket to filter and regulate the slow drip of the water from a plastic bottle over an extended period of time (typically 1-2 weeks). In the −700 device the disk is compressed between the lip of a plastic bottle and a hard plastic spike which is threaded on to the bottle neck. The device described in this application uses a similar multi-layered disk to dispense 3-4 quarts of water over 2-3 weeks, except such disk is designed to be used with a flexible biodegradable bag, rather than the rigid plastic bottle and cap used in the −700 device.
A number of other patents and applications describe devices which have some slight similarities to features of the device disclosed in this application. For example: U.S. Pat. No. 4,554,761 (Tell) is a flexible cover used to protect a plants' reproductive organs from pollination; U.S. Pat. No. 5,252,302 (Schmidt) is a container with an internal cavity which holds a porous bag containing manure and compost; U.S. Pat. No. 5,564,223 (Takita) describes a quick-peelable protective wrap for fruit on a tree; U.S. Pat. No. 5,809,692 (Kesler) is a plant feeder consisting of a water reservoir and connecting conduit; U.S. Pat. No. 5,992,635 (Walters) discloses a pressure release valve for flexible vacuum packages; U.S. Pat. No. 6,243,986 (Crowley) is a plant care system consisting of a root-feeding spike which is gravity fed through a line from a reservoir or bottle; U.S. Pat. No. 6,251,489 (Weiss) is a sterilizable flexible pouch package used for sterilizing objects by steam; U.S. Pat. No. 6,289,630 (Hetze) is a device used to keep flowers fresh by mixing nutrients with liquids; US 2003/010394 (Cook) is a one-way concealed-valve sterilizing objects by steam; U.S. Pat No. 6,289,630 (Hetze) is a device used to keep flowers fresh by mixing nutrients with liquids; US 2003/010394 (Cook) is a one-way concealed-valve vented storage bag; US 2003/0178066 (Skeens) is an evacuable container having a one-way valve with filter element; US 2005/0178066 (Allen) describes a method for forming a vented bag; U.S. Pat. No. 5,171,439 (Vakharia) discloses a liquid non-leaking gas venting seal for a container holding liquid; US 2006/0037884 (Doyle) is a plastic bag for fine powders; JP405124656A (Yamaguchi) describes an air evacuation feed packaging bag and its valve structure and aeration preventing body. This bag, for vacuum cleaners, uses adhesive tape attached to the opposite walls of its inner surface to mount an air suction valve; JP 403172120A (Nishizawa) describes a device for packaging plants, using water-holding polymer materials in a baglike unit, to keep cut plants fresh for a long period.
None of the fifteen patents or applications described in the previous paragraph anticipate any of the key features of the device described in this application, and none could be used in any way to provide water to seedlings over an extended period, as does this invention.